Local area network having multiple channel wireless access

ABSTRACT

A communication network having at least one access point supports wireless communication among a plurality of wireless roaming devices via a first and a second wireless channel. The access point comprises a first and a second transceiver. The first and second transceivers operate on the first and second wireless channels, respectively. Each of the plurality of wireless roaming devices are capable of communicating on the first and second wireless channel. In one embodiment, the first wireless channel is used to exchange data, while the second channel is used to manage such exchanges as well as access to the first channel. In an alternate embodiment, both channels are used to support communication flow, however the first channel supports a protocol that is more deterministic than that of the second channel. Allocation of ones of the plurality of wireless roaming devices from one channel to the next may occur per direction from the access point. It may also result from decisions made by each of the wireless roaming devices made independent of the access point. For example, a decision may be made based on the data type being transferred or based on the current channel load. Such factors may also be used by the access point for allocation determinations. In addition, allocation may be based on the type of roaming device involved, such as allocating peripherals to a slower channel.

[0001] CROSS-REFERENCE To RELATED APPLICATIONS

[0002] The present application is a continuation of co-pending U.S.application Ser. No. 08/878,357 filed Jun. 27, 1997, which is acontinuation-in-part of U.S. application Ser. No. 08/772,895 filed Dec.24, 1996, abandoned, which is a continuation-in-part of U.S. applicationSer. No. 08/696,086 filed Aug. 13, 1996, abandoned, which is acontinuation of U.S. application Ser. No. 08/238,180 filed May 4, 1994,now issued as U.S. Pat. No. 5,546,397, which is a continuation-in-partof U.S. application Ser. No. 08/197,392 filed Feb. 16, 1994, abandoned,which is a continuation-in-part of U.S. application Ser. No. 08/170,121filed Dec. 20, 1993, abandoned.

[0003] The U.S. application Ser. No. 08/772,895 filed Dec. 24, 1996,also claims priority to PCT Application Ser. No. PCT/US96/09474, filedon Jun. 3, 1996.

[0004] All of the aforementioned applications are hereby incorporatedherein by reference in their entirety. In addition, U.S. Pat. No.5,425,051 issued Jun. 13, 1995 to Ronald L. Mahany is also herebyincorporated herein by reference in its entirety.

BACKGROUND

[0005] 1. Technical Field

[0006] The present invention relates generally to access points used inwireless local area networks, and more specifically to an access pointwhich includes multiple wireless adapters.

[0007] 2. Related Art

[0008] Wireless local area networks (WLAN's) use radio frequencytransmissions to communicate between roaming computer devices and accesspoints (or base stations). The access points are connected to aninfrastructure that electronically connects all of the access points toa host system. The wired infrastructure and the access points make up aninformation distribution network used for the transfer of informationand for communications.

[0009] In a wireless networking environment, various types of devicesmay need to communicate within a given area. When incompatibilitiesbetween device types arise, the wireless infrastructure must accommodatethe various device types. Accommodating the different device types in asingle infrastructure is generally difficult to accomplish. Further,devices within the wireless networking environment typically communicatediffering types of data, each with its own priority and bandwidthrequirements. Accommodating the various types of data with their relatedpriorities often could not be accomplished by prior devices due tobandwidth limitations, conflicting priorities and incompatible standardswithin the wireless network.

[0010] In prior WLANs, a first wireless terminal that desired tocommunicate with a base station often could not detect transmissionsfrom a second wireless terminal currently engaged in ongoingcommunication with the access point. As a result, the wireless terminaloften initiated transmissions that collided with the ongoingcommunications. Operation of this type is referred to as a “hiddenterminal” situation. To solve the hidden terminal situation, some priorbase stations were configured with a second transmitter for delivering acarrier signal on a “busy channel” whenever the base station was engagedin communication on the “data channel.” All terminals were also fittedwith a second receiver, tuned to the busy channel, and required to checkthe busy channel before initiating communication on the data channel.However, the additional power required, bandwidth used, hardware neededand associated cost made the busy channel solution undesirable for mostapplications.

[0011] Some prior WLANs attempted to solve operational difficulties bysimply increasing the transmission capacity available on theinfrastructure. Such expansion temporarily decreased conflicts inoperation of the WLANs. However, the infrastructure, which is expensiveto install, typically became overloaded quickly resulting in the same orsimilar problems.

SUMMARY OF THE INVENTION

[0012] The present invention is directed to communication network thatsupports communication within a premises. The communication networkcomprises an access point, a plurality of wireless roaming devices, afirst wireless communication channel, and a second wirelesscommunication channel. The access point itself comprises a firstprocessing circuit, a first radio transceiver coupled to the firstprocessing circuit, and a second radio transceiver coupled to the firstprocessing circuit. Each of the plurality of wireless roaming devicescomprising a second processing circuit, a third radio transceiver and aradio receiver. Therein, the first wireless communication channel thatsupports communication flow via the communication network, while thesecond wireless communication channel is used to manage the flow ofcommunication through the first wireless communication channel. Inaddition, the first and third radio transceivers are operable on thefirst wireless communication channel, while the second radio transceiverand the radio receiver are operable on the second wireless communicationchannel.

[0013] The communication network also supports various other aspects ofthe present invention. For example, the access point may furthercomprise a wired communication interface circuit coupled to the firstprocessing circuit. Selective participation on the first and secondcommunication channels may also provide further benefits. In oneembodiment, each of the plurality of wireless roaming devices utilizesthe radio receiver on the second wireless communication channel beforeparticipating with the third radio transceiver on the first wirelesscommunication channel. In another, each utilizes the radio receiver onthe second wireless communication channel to gain access with the thirdradio transceiver on the first wireless communication channel. Each mayalso or alternatively utilize the second wireless communication channelto identify ongoing communication on the first wireless communicationchannel to, perhaps, provide an indication as to when channel capacitymay become available.

[0014] Other aspects may be found in an alternate communication networkwhich also supports communication within a premises. This communicationnetwork comprises an access point, first and second wirelesscommunication channels and plurality of wireless roaming devices. Thefirst wireless communication channel has first communication flowcharacteristics, while the second wireless communication channel hassecond communication flow characteristics. The first and second radiotransceivers participate on the first and second wireless communicationchannels, respectively. Therein, each of the plurality of wirelessroaming devices comprises a second processing circuit and means forselectively participating on the first and second wireless communicationchannels.

[0015] The access point may also comprise a wired communicationinterface circuit coupled to the first processing circuit that mayitself comprise a first and a second microprocessor. Additionally, atleast one of the plurality of wireless roaming devices may participateon the first wireless communication channel while the other of theplurality of wireless roaming devices participates on the secondwireless communication channel. Although the at least one of theplurality of wireless roaming devices may participate on the firstwireless communication channel as directed by the access device, othervariations and combinations are also possible. For example, at least oneof the plurality of wireless roaming devices may participate on thefirst wireless communication channel to exchange a specific type ofdata, and/or may participate based on current channel conditions. Suchparticipation may be based the fact that, in some embodiments, thesecond wireless communication channel is more deterministic than thefirst wireless communication channel.

[0016] In any of the aforementioned embodiment, the communicationnetwork may comprise at least a second access point. Other variationsand aspects of the present invention will become apparent to ones ofordinary skill in the art after reviewing the entire specification anddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a schematic representation of a high reliability accesspoint in accordance with the present invention.

[0018]FIG. 2 is a schematic representation of another high reliabilityaccess point of the present invention utilizing an antenna diversityscheme at each wireless adapter.

[0019]FIG. 3 is a representation of a distribution network for awireless LAN system utilizing high reliability access points.

[0020]FIG. 4 is a schematic representation of a high reliability accesspoint with a backup power supply.

[0021]FIG. 5 is a schematic representation of a remote high reliabilityaccess point connecting to the distribution network.

[0022]FIG. 6 is block diagram illustrating an embodiment of an accesspoint built in accordance with the present invention which includes tworadios and a wired network interface, a first one of the radios operableon a first channel and a second one of the radios operable on a secondchannel.

[0023]FIG. 7a is a block diagram illustrating an embodiment of aportable data terminal according to the present invention, the portabledata terminal having a single PCMCIA card that contains two radios, afirst one of the radios operable on the first channel and a second oneof the radios operable on the second channel.

[0024]FIG. 7b is a block diagram illustrating an alternative embodimentof the portable data terminal of FIG. 7a, wherein the single PCMCIA cardincludes a single radio operable on the first channel and the secondchannel and controlled by the processing circuitry.

[0025]FIG. 8 is a block diagram illustrating an alternative embodimentof a portable data terminal according to the present invention, theportable data terminal having a single PCMCIA card that contains amulti-channel wireless transceiver and a wired network interface.

[0026]FIG. 9 is a diagram illustrating a communication system built andoperating according to the present invention, the communication systemincluding at least one access point having multiple radios, portableterminals having multiple radios and portable terminals havingmulti-channel radios.

[0027]FIG. 10 is a diagram illustrating a communication system built andoperating according to the present invention wherein one of the accesspoints facilitates communication between portable terminal unitsoperating on different channels within its cell by routing communicationbetween two of its radios.

[0028]FIG. 11 is a block diagram illustrating an embodiment of acommunication system according to the present invention wherein anaccess point uses a dedicated control/busy channel transmitter to managetransmissions between the access point and a plurality of roamingportable data terminals within its cell.

[0029]FIG. 12 is a drawing illustrating advantageous operation of theaccess device and portable data terminals of FIG. 11 when two roamingterminals encounter hidden terminal conditions.

[0030]FIG. 13 is a block diagram illustrating an alternate embodiment ofthe communication system of the present invention wherein an accesspoint includes a dedicated control/busy channel transceiver and roamingdata terminals communicate with the access point using either frequencynimble multi-channel transceivers or dedicated control/busy channeltransceivers.

[0031]FIG. 14a is a block diagram illustrating a communication system ofthe present invention wherein access points and portable data terminalsoperate on a deterministic first channel and a non-deterministic secondchannel and the system routes communications on the channels based uponsystem conditions.

[0032]FIG. 14b is a diagram illustrating operation of a communicationsystem of the present invention having both wired and wirelesscommunication capability that includes at least one access pointproviding communication over a deterministic, time bounded first channeland a non-deterministic, contention access second channel.

[0033]FIG. 15 is a diagram illustrating the use of the access points andportable data terminals of FIG. 14a wherein the system routes varioustransmissions within the network system according to system conditionssuch as channel activity, data type and data priority.

DETAILED DESCRIPTION

[0034] Referring now to the drawings wherein like reference numeralsdesignate identical or corresponding parts throughout the several views,FIG. 1 shows a high reliability access point 10 built in accordance withthe present invention. An access point is a base station on a wirelesslocal area network with which roaming portable or mobile computerdevices can connect and communicate. The access point is typically partof an overall distribution network which is connected to a host computeror entire computer local area network (LAN). The access points and theinfrastructure make up the distribution network and allow forcommunications between the roaming computer devices and the hostcomputer or entire computer local area network (LAN).

[0035] A high reliability access point 10 of the present inventionincludes a central processing unit CPU processor 13 and at least twowireless adapters 15 and 16. Each of the wireless adapters 15 and 16include a radio 17 and 18, a media access control (MAC) processor 19 and20 and an antenna 21 and 22, respectively. The radios and antennas areused for RF transmission and reception. The MAC processor controls lowlevel protocol functions including controlling the operation of theradio, radio channel, error control, e.g., ARQ or Selective Response,and communication with the CPU processor 13. The CPU processor 13controls the high-level communications protocol functions and controlsthe interface 25 between the high reliability access point 10 and theinfrastructure 26. In a preferred embodiment there is a PCMCIA standardinterface between the wireless adapters and the access point.

[0036] The distribution network is comprised of all of the access pointsand the infrastructure which connects all of the access points. A hostcomputer or an entire host network is connected to the distributionnetwork. The distribution network allows computer devices to communicatewith the host computer or host network.

[0037] The division between what is high level protocol, and thushandled by the CPU processor, and what is low level protocol, and thushandled by the MAC processor, can vary greatly depending upon theintelligence level of the MAC processor. In a preferred embodiment, theinfrastructure conforms to an industry standard wired LAN such asEthernet. The MAC processor can be made very intelligent and thereforecapable of handling a great deal of radio specific protocol. On theother hand, the MAC processor can be minimally intelligent and handleonly the most basic protocol functions allowing the CPU processor tohandle the majority of the protocol functions.

[0038] Utilizing multiple wireless adapters in a single access point, aswell as incorporating independent intelligence and low level protocolresponsibility into each wireless adapter, yields several significantadvantages. The examples depicted in FIGS. 1-4 show access points usingonly two wireless adapters per access point. Utilizing two wirelessadapters in the manner discussed below will greatly increase thereliability of a particular access point, as well as increase thereliability of the entire distribution network. Access points could usemore than two wireless adapters and the utilization of the multiplewireless adapters would be similar to the implementation describes usingonly two wireless adapters with addition protocol being required tohandle the increased redundancy and to allow for more sophisticated selfmonitoring.

[0039] Referring still to FIG. 1, the CPU processor 13 can designate theRF address to which each wireless adapter 15 and 16 is to respond. TheCPU processor 13 can, but need not, assign the same address to eachwireless adapter. Therefore, in one configuration, the CPU processor 13can designate that each of the wireless adapters 15 and 16 respond tothe address assigned to that access point 10. Designated as such, bothradios 17 and 18 will be operating simultaneously on the same channel.In a frequency hopping system, both radios 17 and 18 would be operatingon the same hopping sequence, and be mutually synchronized to thathopping sequence.

[0040] Accordingly, the wireless adapters 15 and 16 are configured toreceive incoming transmission from roaming computer devices withinrange. As both wireless adapters 15 and 16 receive the transmission,each adapter can evaluate the quality information to the CPU processor13. The CPU processor 13 uses the quality information to determine whichwireless adapter is receiving the higher quality signal. The CPUprocessor 13 will then typically choose to receive the incomingtransmission on the wireless adapter with the higher signal quality andrespond using the same adapter.

[0041] The antennas 21 and 22 can be positioned to allow the accesspoint 10 to implement an antenna diversity scheme which will help reducethe negative effects caused by multipath interference. Antenna diversitycan be accomplished in various ways. For example, the antennas can beplaced sufficiently far apart, typically greater than a quarterwavelength apart, or the antennas can be positioned at a 90 degree anglewith respect to each other to create a polarization antenna diversityscheme.

[0042] With an antenna diversity scheme in place, the signal from awireless computer device will be received differently on each antennadue to multipath signal propagation. Therefore, each wireless adaptermay receive a signal of a different quality. The CPU processor 13 canchoose which wireless adapter to use based upon the quality of thereceived signal. Each wireless adapter includes the capability ofmeasuring signal quality and only good messages will be forwarded on tothe CPU processor 13. The quality can be appended to the message or canbe presented to the CPU in a memory register.

[0043] Referring now to FIG. 2, another high reliability access point 20built in accordance with the present invention is shown. In thisembodiment, in addition to having an antenna diversity scheme at theaccess point level, there is an antenna diversity scheme at the wirelessadapter level. Each wireless adapter 15 and 16 includes at least twoantennas 21 and 23, 22 and 24, respectively positioned to create anantenna diversity scheme. Thus for the wireless adapter 15 the antennas21 and 23 are either positioned sufficiently far apart, more than aquarter wavelength, or the antennas 21 and 23 are positioned in anasymmetrical or orthogonal manner to provide polarization diversity. Theantennas 22 and 24 for the wireless adapter 26 are placed in a similarmanner.

[0044] In this embodiment, an incoming signal is received on bothantennas 21 and 23 of the wireless adapter 15. The MAC processor 19 thendetermines the quality if the signal coming in on each of the antennas21 and 23 connected to the wireless adapter 15. Based upon the signalquality information, the MAC processor 19 will choose which of theantennas 21 and 23 to use to receive the incoming transmission. The MACprocessor will also forward the signal quality information regarding theselected antenna to the CPU processor 13. The wireless adapter 16 willperform a similar process and forward the signal quality information forits best antenna to the CPU processor 13. The CPU processor 13 can thendetermine which wireless adapter is receiving the highest quality signaland use that wireless adapter to receive the incoming transmission andrespond to the transmitting station.

[0045] When a high reliability access point wishes to transmit amessage, such as an acknowledgment of a received message, to a roamingcomputer device, the CPU processor 13 will utilize the received qualitysignal information to determine which wireless adapter to use to sendthe message. Likewise, if the wireless adapter is utilizing an antennadiversity scheme it will also select the most appropriate antenna fortransmitting a message.

[0046] While one of the wireless adapters is transmitting, the otherwireless adapter can operate as a promiscuous listener to determine ifthe correct message is being sent. For example, referring to FIG. 1, ifthe CPU processor 13 is sending a message to a roaming computer devicevia wireless adapter 16, wireless adapter 17 can operate in the receivemode and monitor the message being sent by the wireless adapter 16. Thisprovides a local loop back capability and allows the access point toperform self-monitoring. If the CPU processor 13 determines that one ofthe wireless adapters is not operating correctly, the malfunctioningwireless adapter can be disabled. Additionally, the CPU processor 13 canthen send a message to the system management portion of the host networkvia the infrastructure 26 that it has a defective wireless adapter andrepairs are needed.

[0047] Referring again to the configuration in which each of thewireless adapters is listening on the same channel, another advantageachieved by this configuration is the ability to receive two concurrentmessages. In an access point that only contains one adapter, thissituation will cause a collision and neither message will be received.In a high reliability access point built in accordance with the presentinvention, it is possible that the one wireless adapter will be able toreceive one of the messages while the other wireless adapter receivesthe other, due to multipath fading at each of the wireless adapterantennas.

[0048] Referring now to FIG. 3, a portion of a distribution network 30utilizing high reliability access points is shown. The distributionnetwork 30 includes an infrastructure 33 and two high reliability accesspoints 35 and 36. Access point 35 includes a CPU processor 37 and twowireless adapters 38 and 39. Access point 36 includes a CPU processor 41and two wireless adapters 42 and 43. In the present example, a break 45in the infrastructure 33 has occurred. Access point 35 is upstream tothe break with respect to the host computer network and thus is notimmediately affected by the break 45. However, access point 36 isdownstream to the break 45 and therefore is no longer connected to thehost computer network.

[0049] When a situation like this occurs, the downstream access point 36will begin attempting to communicate with an upstream access point usingwireless communication. In this example, the upstream access point isaccess point 35. However, the communication need not be with the accesspoint immediately upstream, the only requirement is that it be with anaccess point which is upstream with respect to the break. The hostcomputer network or other access points will previously have shared thelogistic and address information concerning all of the access points toeach access point in the distribution network.

[0050] Once communications with an upstream access point 35 isestablished, each access point 35 and 36 will dedicate one of itswireless adapters 39 and 42, respectively to provide a wireless repairof the break 45 in the infrastructure 33. When this happens, the CPUprocessor for each of the access points will instruct the dedicatedwireless adapter to change so that it is no longer operating on the samechannel as the other adapter in the access point. A communicationchannel between access points is established. The dedicated wirelessadapters 39 and 42 will no longer be used to transmit or receiveinformation to or from roaming computer devices. However, thenon-dedicated wireless adapters 38 and 43 will communicate with theroaming computer devices. Once the top priority of reestablishingcommunications between all of the access points in the distributionnetwork 30 and the host computer network has been accomplished, theaccess points can then send a message to the system management portionof the host computer network detailing where the break (or breaks)exists.

[0051] It is conceivable that the distribution network could lose itsentire infrastructure. In this case, each of the high reliability accesspoints would dedicate one of its wireless adapters to networkinfrastructure communications while retaining one of its wirelessadapters for communication with roaming computer devices. Using the sametechnique described above, a temporary or remote access point could beestablished that, intentionally, is not connected to the infrastructure.This configuration is discussed below in greater detail with referenceto FIG. 5. The use of directional gain antennas for the dedicatedwireless adapter would allow the temporary or remote access point to bepositioned a considerable distance from the infrastructure.

[0052] Referring now to FIG. 4, a high reliability access point 50 witha backup power supply 52 is shown. Typically, the access point will bewired to an external power source 54 such as a wall outlet. However,there is a great desire that if power is lost that the distributionnetwork not shut down since the roaming computer devices will normallynot be dependent upon the external power source 54. In this embodimentof the present invention, the back-up power source 52 is wired inparallel with respect to the external power source 54. Thus, if theexternal power source 54 fails, the access point 50 will not lose power.

[0053] Referring now to FIG. 5, a remote access point 70 is shownconnecting to the infrastructure 33 by means of dedicated wirelessadapters 62 and 72. The access point 70 is not hard wired to theinfrastructure 33. Therefore, the access point dedicates one of itswireless adapters 72 to network infrastructure communication. The otherwireless adapter 74 continues to communicate with roaming computerdevices within the range of the access point 70. An access point 60 thatis hard wired into the infrastructure 33 dedicates one of its wirelessadapters 62 to network infrastructure communication and establishes alink between the infrastructure 33 and the remote access point 70. Theaccess point 60 can continue to service the roaming computer deviceswithin its range through the wireless adapter 64.

[0054] The hard wired access point 60 that is used to connect the remoteaccess point 70 to the infrastructure need not be the access point thatis physically closest to the remote access point 70. Use of thedirectional antenna would allow a remote access point to establishcommunication with virtually any of the access points that are hardwired to the infrastructure. Additionally, several remote access pointscould establish wireless infrastructure communication by each dedicatingone of their wireless adapters. In this arrangement, only one of theremote access points need be in communication with a wired access point.All other remote access points could establish communication with thehost computer network via the remote access point in communication witha wired access point.

[0055]FIG. 6 is block diagram illustrating an embodiment of an accesspoint 600 built in accordance with the present invention capable ofcommunicating with wireless devices in its cell on both a first channeland a second channel. The access point 600 thus includes a first radio616 operating on a first channel and a second radio 608 operating on asecond channel. The access point also includes a processing unit 612 andadditional circuitry 614, both of which couple to the first radio 616,the second radio 608 and a wired Ethernet transceiver through a businterface 610. The wired transceiver 606 allows the access point 600 toaccess a wired LAN backbone 622 to which various other system componentsmay connect. The wired LAN backbone may include, for example, anethernet network, a token-ring network or an asynchronous transfer mode(ATM) network among other network types. In any such case, the wiredtransceiver 606 facilitates communication between the access point 600and devices coupled to the wired LAN backbone 622.

[0056] The blocks illustrated in FIG. 6 are simplified for exemplarypurposes, and it will be understood by one skilled in the art that anaccess point 600 according to the present invention is not limited tothe block circuitry shown in FIG. 6. In another embodiment, the accesspoint 600 may contain additional transceivers for communicating on otherchannels, over other mediums and in other networks as well.

[0057] The first channel radio 616 couples to first antenna 618 whilethe second channel radio 608 couples to second antenna 620. The antennas618 and 620 may either be protruding or non-protruding antennas,depending upon system requirements. The first channel radio 616 and thesecond channel radio 608 operate independently to form a firstcommunication cell and a second communication cell, respectively. When aradius of the first communication cell substantially equals a radius ofthe second communication cell, the cells substantially overlay oneanother. However, when the radii of the communication cells differ, thelarger cell fully overlays and extends beyond the smaller cell. Thefirst and second channels may operate using different frequencies,modulation schemes and code spreading schemes. The selections of suchoperational channel variations depend on overall system constraints, yetshould result in two independent channels that do not interfere with oneanother unacceptably.

[0058] The bus interface 610 isolates the processing unit 612 and theadditional circuitry 614 of the access point 600 from the operatingcharacteristics of the radios 616 and 608 and the wired transceiver 606.Thus, communication with any of the transceivers can be accommodated bygeneral circuitry and software routines of the access point 600. In oneembodiment, the bus interface 610 is a PCI bus interface with the firstchannel radio 616, second channel radio 606 and wired transceivercompatible with PCI bus standards. However, in other embodiments,differing interface standards may be employed.

[0059] In operation, the processing unit 612 is programmed with thenetwork configuration to route communications through the first channelradio 616, the second channel radio 608 and the wired transceiver 606.However, roaming portable units may alter the network configuration asthey move between cells. Thus, the access point 600 periodically pollsdevices within its communication cell to update the networkconfiguration. Updates are entered and forwarded for other units in thesystem.

[0060] Incoming messages received via the wired transceiver 606 may bestored, displayed and routed via the first channel radio 616 or routedvia the second channel radio 608 to portable data terminals or otherwireless devices operating within the cell(s) of one or more of theaccess point 600. Similarly, an incoming message on one of the radios616 or 608 may be stored, displayed, routed through one of the radios616 or 608 or routed through the wired transceiver 606, depending uponthe message destination and type.

[0061] By providing routing within the access point 600 between thefirst channel radio 616 and the second channel radio 608, messagedelivery is expedited. Further, as will be described herein, byproviding two radios in various access points, fewer cells may berequired to adequately service a premises such as a factory. Moreover,when one of the radios is employed to provide control within a cellwhile the other radio provides primary communication within the cell,collisions between devices may be eliminated. Still further, when one ofthe radios provides a deterministic communication path while another oneof the radios provides a non-deterministic communication path, data andmessage transmissions within the network may be controlled to satisfybandwidth requirements of the various devices within the system. It maybe preferable to utilize a deterministic communication path for sometypes of communications such as telephony video or real-time datatransfer, for example. However, when the preferred deterministic path isunavailable for some reason, the alternative non-deterministic path maystill be used.

[0062] The access point 600 may synchronize transmissions on the firstchannel radio 616 and the second channel radio 608 to avoid unacceptableconflicts between transmissions on one radio and receipts on the otherradio. In this fashion, unacceptable conflicts are minimized.

[0063]FIG. 7a is a block diagram illustrating an embodiment of aportable data terminal 720 according to the present invention, theportable data terminal having a single PCMCIA card that contains tworadios. In particular, the portable data terminal 720 contains terminalcircuitry 722 that includes processing circuitry 726, conventionalterminal circuitry 728 and interface circuitry 730. The interfacecircuitry 730 provides a PCMCIA interface for receiving PCMCIA cards ofvarious functionality. Terminal circuitry 722 is well known and can befound in conventional portable or hand held computing devices.

[0064] Via the interface circuitry 730, the portable data terminal 720accepts PCMCIA cards. As illustrated, the PCMCIA card insertedconstitutes a communication module 724 that provides wireless access ontwo channels. Specifically, the communication module 724 comprisesprocessing circuitry 732, first channel radio 735, second channel radio734 and interface circuitry 744. The first channel radio 735communicates via first antenna 737 while the second channel radio 734communicates via second antenna 738. Configured and operable in thismanner, the portable data terminal 720 may communicate with the accesspoint 600 of FIG. 6 on either the first channel or the second channel.

[0065] Independent of whether the first channel radio 735 or the secondchannel radio 734 is used, the processing circuitry 726 delivers andreceives data and messages via the interface circuitry 730 in the samemanner and format, i.e., the interface circuitry 730 supports a commoncommunication interface and protocol. The processing circuitry 732 ofthe communication module 724 receives data and messages via theinterface circuitry 744. The processing circuitry 732, including a DSP742, participates to assist in wireless communication via both the firstchannel radio 735 and the second channel radio 734. Thus, the module 724not only saves on PCMCIA slots, but also saves costs and increasesreliability by sharing common circuitry resources. In particular, thefirst channel radio 735 and second channel radio 734 share the interfacecircuitry 744 and processing circuitry 732 which includes the DSP 742.In another embodiment of the portable data terminal 720, a PCMCLAcompatible wired network adapter could be installed which would alsoshare some of the common circuitry resources.

[0066]FIG. 7b is a block diagram illustrating an alternative embodimentof a portable data terminal 748 that receives a single PCMCIA cardhaving a radio 750 that includes two separate radio units. As contrastedto the dual radio design of the portable data terminal 720 of FIG. 7a,the radio 750 of the portable data terminal 748 of FIG. 7b operates onboth the first channel and the second channel. The radio 750 is coupledto antenna 756 and controlled by processing circuitry 752 that includesdigital signal processing circuitry 754. The radio 750 includes a firstradio unit operable on the first channel and a second radio unitoperable on the second channel with the radio units sharing some commoncomponents.

[0067] The processing circuitry 752 may control operation of the radio750 in a simplex fashion such that the radio 750 operates on the firstchannel as required and operates on the second channel as required.Because the radio 750 may includes circuitry shared by the radio units,the radio 750 may only operate on one channel at a given time. Bymultiplexing its operation over time, however, the radio 750 providessufficient coverage on the channels at a reduced cost. Other componentsof the portable data terminal of FIG. 7b were previously described withreference to FIG. 7a and will not be further described herein.

[0068]FIG. 8 is a block diagram illustrating an alternative embodimentof a portable data terminal 800 according to the present invention, theportable data terminal 800 having a single PCMCIA card that contains amulti-channel (or multi-mode) wireless transceiver 739 and a wirednetwork interface 736 (or modem transceiver). The portable terminal 800includes terminal circuitry 722 and a module 802 including variouscomponents previously described with reference to FIG. 7a. The terminalcircuitry 722 includes processing circuitry 726, conventional terminalcircuitry 728 and interface circuitry 730. The communication module 802includes processing circuitry 732, the multi-mode wireless transceiver739, the wired modem transceiver 736 and interface circuitry 744. Whenin use, the wired modem transceiver 736 interfaces via a jack 740 to atelephone line (not shown). Similarly, the wireless multi-modetransceiver 739 communicates via an antenna 741.

[0069] The processing circuitry 732 of the communication module 802receives data and messages via the interface circuitry 744. If the modemtransceiver 736 is being used, the processing circuitry 732appropriately (de)segments and (de)compresses the data/messagesutilizing a digital signal processor (DSP) 742. Otherwise, theprocessing circuitry 732, including the DSP 742, participate to assistin wireless communication via the multi-mode transceiver 739. Thus, themodule 802 not only saves on PCMCIA slots (as required when aconventional radio card and a conventional modem card are both beingused), but also saves costs and increases reliability by sharing commoncircuitry resources.

[0070] The multi-mode transceiver 739 is frequency nimble and mayoperate in various modes, such as those that may be used with afrequency spreading scheme such as those described in U.S. Pat. No.5,425,051 issued Jun. 13, 1995 to Ronald L. Mahany, which isincorporated herein by reference. Thus, the multi-mode transceiver 739may operate on both the first channel and the second channel andcommunicate with the access point 600 of FIG. 6 on either the firstchannel or the second channel. As will be further described herein,operation on differing channels may be employed to reduce installedsystem component requirements, to alleviate various potentialinterfering operating conditions and to more efficiently route data andmessages within the wireless local area network.

[0071]FIG. 9 is a diagram illustrating a communication system 900 builtand operating according to the present invention. The communicationsystem includes an access point 902 operating on two channels and accesspoints 904 and 906 operating on a single channel. Each of the accesspoints 902, 904 and 906 connects to a wired LAN backbone 908 tofacilitate wired communication between the access points and computersystems 910 and 912 connected to the wired LAN backbone 908.

[0072] Access point 902 includes both a first channel radio and a secondchannel radio. In the embodiment illustrated, the first channel radiocreates a first channel cell 930 extending with a first channel radiusabout the access point 902. The second channel radio of the access point900 creates a second channel cell 932 extending with a second channelradius about the access point 902. As illustrated, the second channelcell 932 has a larger radius than the radius of the first channel cell930. To create the relatively larger cell, the second radio may operateat a higher power, operate at a lower data rate or operate in anotherdiffering manner to create the relatively larger cell.

[0073] Access points 904 and 906 generate first channel cells 934 and936, respectively. Portable data terminals 920, 922, 924 and 926 andscanning unit 918 communicate with the various access points 902, 904and 906 and roam about the communication system 900, potentially movingfrom cell to cell. Other devices, such as stationary printers 914 and916 typically remain within one cell of the communication system 900. Inthe embodiment illustrated, portable data terminals 920 and 926 includemulti-mode radios while portable data terminals 922 and 924 include botha first channel radio and a second channel radio. However, in otherembodiments, some of the portable data terminals may only on one of thechannels.

[0074] As illustrated, terminal 922 includes a first channel antenna 940and a second channel antenna 942 while access point 902 includes both afirst channel antenna 944 and a second channel antenna 946. Thus,whenever the terminal 922 roams within the second channel cell 932, theterminal 922 communicates via a second channel radio and second channelantenna 942. Further, terminal 950 may communicate with access point 902on the first channel via its first channel antenna 954 when residentwithin the first channel cell 903. Finally, terminal 952, having asingle radio operable the first channel via antenna 956 may communicatewith access point 902 on the first channel when resident within thefirst channel cell 932.

[0075] As shown, portable data terminal 922 resides both within thefirst channel cell 930 and the channel cell 932 generated by accesspoint 902. Thus, the portable data terminal 922 may communicate withaccess point 902 on either the first channel or the second channel.However, printer 916 and scanning unit 918 reside only within the secondchannel cell 932 generated by access point 902 and must communicate withthe access point 902 on the second channel.

[0076] Print data originating at computer 910 and intended for printer916 travels from computer 910, through the wired LAN backbone 908 toaccess point 902 and across first channel cell 932 to the printer 916.During this transmission, the data is routed through the wired LANbackbone and the wireless network based upon the network locations ofthe computer 910 and the printer 916. The combination of these segmentsforms a unique network path. However, a message moving from portabledata terminal 926 to portable data terminal 922 may be routed along twodifferent network paths. While both network paths include access point906, wired LAN backbone 908 and access point 902, one network pathincludes first channel cell 930 while the other network path includessecond channel cell 932. Thus, depending upon system conditions and thesystem configuration, the message is routed via one of the two networkpaths. Such conditions may include cell traffic, required data rates andother factors.

[0077]FIG. 10 is a diagram illustrating a communication system 1000built and operating according to the present invention wherein one ofthe access points routes communication between two portable terminalunits operating on different channels within its cell. In thecommunication system 1000, both a first access point 1002 and a secondaccess point 1004 include both first and second channel radios. Thefirst access point 1002 generates a first channel cell 1006 and a secondchannel cell 1008 within which portable data terminals 1012 and 1014operate. Further, second access point 1004 generates a first channelcell 1010 and a second channel cell 1011 within which portable dataterminals 1012 and 1014 may operate. In the embodiment, the system 1000prefers to route communication on the first channel due to itscharacteristics although the portable data terminals may operate oneither channel.

[0078] As illustrated, portable data terminal 1012 resides within boththe first channel cell 1006 and the second channel cell 1008 generatedby access point 1002. However, portable data terminal 1014 resides onlywithin the second channel cell 1008 of the access point 1002. Thus, inthe transmission of a message from portable data terminal 1012 toportable data terminal 1014, access point 1002 receives the message fromportable data terminal on the first channel radio and transmits themessage to portable data terminal 1014 on the second channel. Withreference to FIG. 6, the processing unit 612 receives the message viathe first channel radio 616 across the bus interface 610. The processingunit 612 determines the destination of the message, and routes themessage back across the bus interface 610 to the second channel radio608 that transmits the message to portable data terminal 1014. Accesspoint 1004 also provides multiple channel routing of messages betweenportable data terminals 1016 and 1018.

[0079] Without the multiple channel communication capabilities of thecommunication system 1000, an additional access point 1020 having afirst channel cell 1022 would be required to facilitate communicationwith portable data terminals 1014 and 1018. The cost of such anadditional access point 1020 would not only include the cost of theaccess point 1020 itself but the expense of connecting the access point1020 to the wired LAN backbone 908 and AC power. The cost of suchaddition would far exceed the cost of the second channel radios inaccess points 1002 and 1004. Furthermore, in some installation,extensions of the wired LAN backbone 908 are not possible. Even if suchaccess point 1020 were installed, the exemplary communication wouldrequire routing of messages between portable data terminal 1012 and 1014across the wired LAN backbone 908. Such additional loading slowsoperation of the wired LAN backbone 908 and decreases systemperformance.

[0080]FIG. 11 is a block diagram illustrating an embodiment of acommunication system 1100 according to the present invention wherein anaccess point 1102 uses a dedicated control/busy channel transmitter 1114operating on a busy/control channel to manage transmissions between theaccess point 1100 and a plurality of roaming portable data terminals1104 and 1106 within its cell. The communication system may also containwired communication to a wired Ethernet backbone LAN 908.

[0081] The access device 1102 includes control circuitry 1120, a datatransceiver 1118, a busy/control transmitter 1114 and antennas 1115 and1117. The data transceiver 1117 supports communication on acommunication channel (first channel) between the access point 1102 andwireless network devices operating within range of the access point,such as the portable data terminals 1104 and 1106. Further, thebusy/control transmitter 1114 supports transmissions on the busy/controlchannel (second channel). The Ethernet transceiver 1115 supportscommunication between the backbone LAN 908 and the control circuitry1120.

[0082] Portable data terminals 1104 and 1106 include terminal circuitry1112, a data transceiver 1108 that communicates on the communicationchannel via antenna 1109 and a busy/control receiver 1110 that receivesbusy/control information via antenna 1111. As previously described, thecommunication channel and the busy/control channel are non-convergentand may operate concurrently in a single area or location. However, theaccess point 1102 must operate so as not to interfere with incomingtransmissions by concurrently initiating a transmission. Thus, in oneembodiment, transmissions on the communication channel and thecontrol/busy channel are synchronized to prevent such conflicts.

[0083] The access point 1102 employs the busy/control transmitter 1114to control operations within the first wireless network cell. In oneembodiment, the access point 1102 periodically transmits controlparameters that the portable data terminals 1104 and 1106 use tosynchronize with communications on the communication channel. Forexample, with the data transceiver of the communication channeloperating in a spread spectrum mode, the busy/control transmitter 1114transmits code spreading sequences, frequency hopping parameters andother operating parameters that allow the portable data terminals 1104and 1106 to communicate within the cell on the communication channel.Such control information may be intermittently transmitted by the accesspoint 1102 or may be continuously transmitted.

[0084] Additionally, the access point 1102 transmits a busy signal onthe busy/control transmitter 1114 to authorize communication within thecell. To prevent portable data terminal 1104, for example, fromtransmitting while portable data terminal 1106 is communicating with theaccess point 1102, the access point 1102 transmits a busy signal on thebusy/control channel using the busy/control transmitter 1114. Theportable data terminal 1104 receives the busy signal and does nottransmit information while such busy signal is active, perhaps enteringa sleep mode instead and waking up periodically to determineavailability. The busy signal may include a continuous transmission orperiodic transmission. However, in both embodiments, portable dataterminals 1104 and 1106 listen with their respective control/busyreceivers 1110 prior to initiating communication with the access point1102. Thus, upon roaming into range of the wireless access device 1102,the portable data terminals 1104 do not interfere with ongoingcommunication.

[0085]FIG. 12 is a drawing illustrating advantageous operation of theaccess device and portable data terminals of FIG. 11 when two roamingterminals encounter hidden terminal conditions. In particular, each ofthe portable data terminals 1208 and 1212 is configured to listen on thebusy/control channel and to communicate on the communication channelonly when the communication channel is clear (available). In thisconfiguration, when no desire to communicate is present, the portabledata terminals 1208 and 1212 need only occasionally check thebusy/control channel to identify any outstanding messages orcommunication requests as transmitted by the access device 1202. Ifeither portable data terminal 1208 or 1212 desires to participate on thecommunication channel (to initiate communication or to respond toawaiting messages or communication requests), that terminal need onlymonitor the busy/control channel long enough to identify that thecommunication channel is clear before responding to a poll on thecommunication channel. As before, the wireless access device 1202 mayalso periodically identify the communication channel mode and associatedparameters as selected and reselected by the wireless access device1202.

[0086] To fully appreciate this process, first assume that the portabledata terminals 1208 and 1212 are not within range of the wireless accessdevice 1202. Upon wandering within range of the access device 1202, theportable data terminal 1212 begins listening for transmissions on abusy/control channel. Within some time period thereafter, the accessdevice 1202 participates on the busy/control channel to transmit currentchannel conditions and optionally, the currently selected communicationchannel definition (i.e., mode and parameters) and/or pending messageand communication request indicators. After identifying a need toparticipate, the portable data terminal 1212 awaits a transmission fromaccess device 1202 (on the busy/control channel) that the selectedcommunication channel is clear (not in use). When the channel is clear,the portable data terminal 1212 begins participating thereon.

[0087] Second, assume that, while the portable data terminal 1212 isengaged in ongoing communication with a computing device 1206 on abackbone LAN 908 via the access device 1202, the portable data terminal1208 comes within range of the access device 1202 and desires toparticipate on the communication channel. The portable data terminal1208 adapts itself to participate on the busy/control channel andidentifies, in periodic transmissions from the access device 1202, thatthe communication channel is busy. Thus, the portable data terminal 1208must monitor the busy/control channel to identify when the communicationchannel is clear before participating on the communication channel.

[0088] This operation works whether or not the portable data terminals1208 and 1212 are within range of each other. In particular, portabledata terminal 1208, portable data terminal 1212 and access device 1202have transmission ranges illustrated by dashed circles 1210, 1214 and1204, respectively. Although both portable data terminals 1208 and 1212are within range of the access device 1202, neither are in range of eachother and, thus, are referred to as “hidden” from each other. The accessdevice 1202 is within range of both of the portable data terminals 1208and 1212. If the portable data terminal 1208 attempted to transmit onthe communication channel while the portable data terminal 1212 wastransmitting, a collision would occur at the wireless access device1202. However, this is not the case because both of the portable dataterminals 1208 and 1212 must receive a communication channel clearindication on the busy/control channel from the access device 1202 thatis in range of both, avoiding the hidden terminal problem. Whenparticipation is completed on the communication channel, the portabledata terminals 1208 and 1212 resume monitoring of the busy/controlchannel.

[0089] Participation by the access device 1202 on the busy/controlchannel need only be by transmitting, although receiving might also beemployed in case the busy/control channel is to be shared. Similarly,participation by the portable data terminals 1208 and 1212 need only beby receiving transmissions, although transmitting might also beemployed. In particular, transmission might be employed by a wirelessterminal on the busy/control channel if the wireless terminal does notsupport the currently selected communication channel, i.e., does notsupport the mode and associated parameters.

[0090]FIG. 13 is a block diagram illustrating an alternate embodiment ofthe communication system 1300 of the present invention wherein an accesspoint 1302 includes a dedicated control/busy channel transceiver 1310and roaming data terminals 1304 communicate with the access point 1302using either frequency nimble multi-channel transceivers 1305 or adedicated control/busy channel transceiver 1326. Thus, the communicationsystem 1300 facilitates bi-directional communication on the busy/controlchannel so that the access point 1302 may optimize operation of thesystem 1300.

[0091] In addition to the busy/control transceiver 1310 coupled toantenna 1314, the access point includes control circuitry 1306, a datatransceiver 1312 coupled to antenna 1316 that facilitates wirelesscommunication on the communication channel and an Ethernet transceiver1308 that couples the access point 1302 to the backbone LAN 908.Portable data terminal 1304 includes terminal circuitry 1112 and amulti-mode/multi-channel transceiver 1305 that allows the portable dataterminal 1304 to communicate both on the busy/control channel and thecommunication channel. Portable data terminal 1320 includes terminalcircuitry 1322, a busy/control transceiver 1324 coupled to antenna 1330that allows the portable data terminal 1320 to communicate on thebusy/control channel and a data transceiver 1326 coupled to antenna 1328that allows the portable data terminal to communicate on thecommunication channel.

[0092] Having separate radio units and antennas, the access device 1302participates on: 1) a selected communication channel, servicing dataexchanges in the communication network cell; and 2) the busy/controlchannel defined by predetermined mode and parameter information known toall wireless transmitters, controlling access to the selectedcommunication channel. Such participation is often simultaneous,preventing a portable data terminal 1304 or 1320 from having to waitlong on the busy/control channel for a transmission. Within a predefinedmaximum time period, the portable data terminal 1304 or 1320 receivestransmissions from the access device 1302 identifying currently selectedcommunication channel mode and associated parameters, should such berequired. The access device 1302 periodically broadcasts suchinformation on the busy/control channel to capture terminals that happento need communication channel definitions (e.g., selected mode andparameters) to participate. The portable data terminal 1304 utilizes theidentified mode and associated parameter information to switch themulti-mode transceiver 1305 over to the selected communication channeland begins participation thereon. Portable data terminal 1320 may alsoalter the operation of the data transceiver 1326 based upon the receiptfrom the access point 1302.

[0093] In operation, the wireless terminal 1304 participates on thebusy/control channel except when it has a need to gain access to theselected communication channel. Thus, its operation in the system 1300is satisfactory. By including only the terminal circuitry 1112 and oneradio, the portable data terminal is less costly than the multi-radioportable data terminal 1320. However, because the wireless terminal 1320includes two radios, the portable data terminal 1320 may place the datatransceiver 1326 in a low power state, and only power up thebusy/control channel transceiver 1324 to check in. Thus, portable dataterminal 1320 may consume less power that portable data terminal 1304.

[0094]FIG. 14a is a block diagram illustrating a communication system1400 according to the present invention wherein an access point 1402 andportable data terminals 1404 and 1406 operate on a deterministic firstchannel and a non-deterministic second channel and the system 1400routes communications on the channels based upon system conditionsand/or the requirements of a particular communication. To carry out suchfunctionality, the access device 1402 may comprise control circuitry1408, a wired LAN transceiver 1410 and either a single, configurabletransceiver (for operating on both the deterministic andnon-deterministic channels, not shown) or a single transceiver 1412coupled to antenna 1413 for operating on the deterministic channel and asingle transceiver 1414 coupled to antenna 1415 for operating on thenon-deterministic channel.

[0095] In one embodiment, the deterministic channel allocates aparticular communication bandwidth to each wireless device requiringcommunication, perhaps in a polled, token passing or time slottedimplementation. Such operation may be required where many wirelessdevices reside within a single cell and compete for communication withthe access point 1402. In the embodiment, the access point 1402 alsoallows all devices within the cell to compete for available bandwidth onthe non-deterministic channel. However, the access point 1402 mayprovide overrides to dynamically reallocate bandwidth in thedeterministic channel and to assign bandwidth on the non-deterministicchannel as may be required for the particular operating conditions.

[0096] With a single multi-mode transceiver 1418 coupled to antenna 1419controlled by terminal circuitry 1416, the portable data terminal 1404operates on either the deterministic channel or the non-deterministicchannel at any time. Alternatively, portable data terminal 1406 havingterminal circuitry 1420, a deterministic transceiver coupled to antenna1425 and a non-deterministic transceiver 1422 coupled to antenna 1423communicate on both the deterministic channel and non-deterministicchannel simultaneously.

[0097] Independent of their differing constructions, the portable dataterminals 1404 and 1406 may determine which channel to operate upon.During data transfer operations wherein data transfer rates are notcritical, portable data terminal 1404 may determine that thedeterministic channel provides sufficient bandwidth. In that case, theportable data terminal 1404 configures its multi-mode transceiver 1418to operate on the deterministic channel. However, during voice messagetransfer operations, the portable data terminal 1404 may determine thatthe bandwidth of the deterministic channel is not satisfactory. In thatcase, the terminal circuitry 1404 would configure the multi-modetransceiver 1418 to operate on the non-deterministic channel.

[0098]FIG. 14b is a diagram illustrating a communication system 1450according to the present invention that facilitates both wired andwireless communications. The communication system 1450 includes a wiredbackbone 1452 and at least one access point 1456 that supportscommunication over a deterministic, time bounded first wireless channeland a non-deterministic, contention access second wireless channel.Along with the access point 1456, the communication system 1450 may alsoinclude a PBX (Private Broadcast Exchange) system 1454, one or more of acomputer 1454, and other typical wired network devices interconnected bythe wired backbone 1452. Additionally, the communication system 1450comprises a plurality of wireless network devices, such as wirelessterminals 1470, 1472 and 1474, which may be portable hand-held devices,mobile computing devices, laptop computers, wireless peripherals, etc.

[0099] Communication upon the wired backbone 1452 may be accomplishedaccording to various communication techniques. In one embodiment,communication upon the wired backbone 1452 occurs via an STM(Synchronous Transfer Mode) protocol wherein the wired backbone 1452serves as an STM backbone. With the STM protocol, a particular bandwidthis provided for each communication link established between a sendingand a receiving device attached to the wired backbone 1452.

[0100] In another embodiment, communication upon the wired backbone 1452is carried out using an ATM (Asynchronous Transfer Mode) protocol inwhich bandwidth between a sending and a receiving device on the wiredbackbone 1452 is adjusted based upon immediate communicationrequirements. In such operation, the wired backbone 1452 serves as anATM backbone. Operation according to the ATM protocol allows forvariations in data transmission bandwidths as is immediately requiredbut that provides an average bandwidth over time.

[0101] The at least one access point 1456 provides a link between thewireless and wired communications within the communication system 1450.The access point 1456 includes a time bounded adapter 1458 connected toan antenna 1460 which provides wireless communication on thedeterministic, time bounded first wireless channel governed by a firstwireless protocol. The access point 1456 also includes a contentionadapter 1462 connected to an antenna 1464 which provides wirelesscommunications on the non-deterministic, contention access secondwireless channel governed by a second wireless protocol. Alternatively,part or all of the circuitry underlying the adapters 1458 and 1462 maybe combined into a single unit to share common underlying functionality.

[0102] The wireless network device 1470 includes either a dual purposetransceiver or two transceivers for communicating on the first andsecond wireless channels via the first and second wireless protocols,respectively. A transceiver in the wireless network device 1472 onlysupports communication on the second wireless channel pursuant to thesecond wireless protocol. Likewise, a transceiver in the wirelessnetwork device 1474 supports communication on the first wireless channelpursuant to the first wireless protocol. For example, the wirelessnetwork device 1474 might comprise a portable phone unit operatingusing, e.g., PCS (Personal Communication Service) or other telephonyprotocol as the first wireless protocol.

[0103] Although direct communication is possible, to manage the firstwireless channel, the at least one access point 1456 relays wirelesscommunication between the wireless network devices 1470 and 1474 if bothparticipate on the first wireless channel. If the at least one accesspoint 1456 is the only access point involved that services the twodevices 1470 and 1474, such relaying need not involve the wired protocolon the backbone 1452. If the device 1470 happens to communicate via thesecond wireless channel, the access point 1456 internally translates andrelays communications between the devices 1470 and 1474. Similarly, ifthe device 1470 intends to communicate with a wired network device usingeither the first or second wireless protocol, the access point 1456utilizes the first or second wireless protocols, respectively, tocommunicate with the device 1470. The access point 1456 alsocommunicates with the target wired network device, e.g., the computer1454, via the wired communication protocol. Relaying between the wiredand wireless channels also requires translation.

[0104] If more than one access point is coupled to the wired backbone1452, for example, to support many more wireless network devices,roaming wireless network devices and/or extended coverage regions, theaccess points only utilize wired backbone bandwidth if necessary. Eachaccess point attempts to minimize external bandwidth (of wired andwireless channels) by preferring internally performed relaying and, whenneeded, translation (between the first and second wireless protocols, orbetween the wired protocol and either the first or the second wirelessprotocol).

[0105] The PBX system 1454 connects the wired backbone 1452 through aswitched telephone network to other communication systems such as thesystem 1452. This facilitates communications between all wireless andwired network devices, such as the computer 1454, the device 1470 andremote network devices (devices) connected elsewhere to the switchedtelephone network. In circuit switched applications, a VLAN (virtuallocal area network) can be established between wired and wirelessnetwork devices coupled to the wired backbone 1452. Such coupling alsoincludes remote network devices coupled via the PBX system 1454.

[0106]FIG. 15 is a diagram illustrating the access point 1402 andportable data terminals 1404 and 1406 of FIG. 14a wherein a system 1500routes various transmissions according to system conditions such aschannel activity, data type and data priority. In the system 1500,access point 1402 forms cell 1512 while access point 1504, operating ononly a single channel, forms cell 1514. Thus, while access point 1402must determine how to allocate wireless communications among thedeterministic channel and non-deterministic channel in its cell 1512,access point 1504 routes all communications on its only channel.

[0107] In a first example of the operation of the system 1500, data fromcomputer system 1502 is transmitted to portable data terminal 1406. Thecomputer system 1502 transmits the data through the wired LAN backbone908 to the access point 1402. The access point 1402, having adeterministic transceiver 1412 and a non-deterministic transceiver 1414,routes the data through one of the transceivers. Based upon the type ofdata, the quantity of data, the rate at which data may be passed oneither channel, the amount of traffic on the channels and otherconditions, the control circuitry 1408 in the access point 1402 routesthe data on either the non-deterministic channel via thenon-deterministic transceiver 1414 or on the deterministic channel viathe deterministic transceiver 1412. In the present example, the data tobe transferred has a relatively low priority and the access point routesthe data on the deterministic channel to the portable data terminal1404. Likewise, print jobs from the computer 1402 to the printer 1510would also have relatively low priority and be transmitted via thenon-deterministic channel.

[0108] Next, consider data transmissions from scanner 1508 to computersystem 1502. During operation, the scanner transmits an image to thecomputer system 1502 for decoding and the computer system 1502 returnsdecoded information at which point the scanner ceases scanning. Rapidtransmission between the scanner 1508 and the computer system 1502reduces the time within which the scanner 1508 performs scans. Thus,rapid transmissions may reduce energy consumption in the scanningprocess that drains battery life of the scanner 1508. Thus, the scanner1508 and access point 1402 both attempt to transmit data on thenon-deterministic channel at a relatively higher data transfer rate.However, if the non-deterministic channel is unavailable, thetransmission on the deterministic channel may be satisfactory.

[0109] In the case of a voice message transmission from portable dataterminal 1506 in cell 1514 to portable data terminal 1404 in cell 1512,transmission on the deterministic channel may be unsatisfactory. Thus,upon an incoming voice message transmission, the access point 1402 mayreallocate the deterministic channel allocating additional bandwidth forthe voice message. In an alternative operation, the access point 1402may interrupt communication on the non-deterministic channel andtransmit the voice message to the portable terminal unit 1404 on thenon-deterministic channel. Thus, in the mode of operation of the system1500 modifies its operation to provide sufficient bandwidth for thevoice message.

[0110] In view of the above detailed description of the presentinvention and associated drawings, other modifications and variationswill now become apparent to those skilled in the art. It should also beapparent that such other modifications and variations may be effectedwithout departing from the spirit and scope of the present invention asset forth in the claims that follow.

What is claimed is:
 1. A communication network for collecting andcommunicating data, comprising: a wireless access device comprising acontrol circuit and a first RF transceiver that selectively operates inone of a plurality of spread spectrum modes; at least one mobileterminal comprising a second RF transceiver that operates in at leastone of a plurality of spread spectrum modes; and the control circuitresponsive to transmissions received from the first RF transceiver forevaluating communication performance and dynamically selecting one ofthe plurality of spread spectrum modes of the first RF transceiver whiletaking into consideration at least one of the plurality of spreadspectrum modes of the second RF transceiver.
 2. The communicationnetwork of claim 1 wherein the plurality of spread spectrum modes of thefirst RF transceiver comprising a direct sequence transmission mode anda frequency hopping mode.
 3. The communication network of claim 1wherein the plurality of spread spectrum modes of the first REtransceiver comprising a direct sequence transmission mode and achannelized direct sequence mode.
 4. The communication network of claim1 wherein the plurality of spread spectrum modes of the first RFtransceiver comprising a frequency hopping mode and a hybrid frequencyhopping mode.
 5. The communication network of claim 1 wherein said firstRF transceiver operates to support a communication channel and abusy/control channel on a timeshared basis.
 6. In a communicationnetwork, a plurality of wireless access device capable of communicatingwith a plurality of wireless terminals, each of the plurality ofwireless access device comprising: a first radio controllable to supporta communication channel operating pursuant to one of a plurality ofmodes; a second radio supporting a busy/control channel independent ofthe communication channel; a controller that selects one of theplurality of modes and controls the first radio to support theselection; and the controller utilizes the second radio to communicateon the busy/control channel to manage the communication channel.
 7. Inthe communication network of claim 6, wherein the plurality of modesincludes a plurality of spread spectrum modes.
 8. In the communicationnetwork of claim 7, wherein the first radio comprises a multimode radioand the second radio comprises a transmitter.
 9. In a communicationnetwork, a plurality of wireless access device capable of communicatingwith a plurality of wireless terminals each of the plurality of wirelessaccess device comprising: a transceiver controllable to operate pursuantto any of a plurality of communication modes; a controller that selectsfrom the plurality of modes a communication channel and an independent,busy/control channel; and the controller controls the transceiver tosupport data routing on the communication channel while managing accessto the communication channel while managing access to the communicationchannel via the busy/control channel.
 10. In the communication networkof claim 9, wherein the plurality of communication modes includes aplurality of spread spectrum modes.
 11. An access point forcommunicatively coupling a first roaming wireless device and a secondroaming wireless device to a wired link, the access point comprising: ahousing; a control circuit disposed in the housing; a wired transceiver,disposed in the housing, that is communicatively coupled to the controlcircuit and the wired link; a first wireless transceiver, disposed inthe housing, that is communicatively coupled to the control circuit, thefirst wireless transceiver operating on a first wireless communicationchannel to communicatively couple with the first roaming wirelessdevice; a second wireless transceiver, disposed in the housing, that iscommunicatively coupled to the control circuit, the second wirelesstransceiver operating on a second wireless communication channel tocommunicatively couple with the second roaming wireless device; and thecontrol circuit accommodates communications between the first wirelesstransceiver and the second wireless transceiver exclusive of the wiredlink.
 12. The access point of claim 11, further comprising a businterface communicatively coupling the control circuit to the first andsecond wireless transceivers and the wired transceiver.
 13. The accesspoint of claim 12, wherein the bus interface is substantially compliantwith a bus standard.
 14. The access point of claim 13, wherein the busstandard is the PCI standard.
 15. The access point of claim 11, whereinthe wired transceiver accommodates communication with an ethernetnetwork.
 16. The access point of claim 11, wherein the wired transceiveraccommodates communication with a token-ring network.
 17. The accesspoint of claim 11, wherein the wired transceiver accommodatescommunication with an asynchronous transfer mode network.
 18. The accesspoint of claim 11, wherein the wired transceiver accommodatescommunication with a packetized network.
 19. The access point of claim11, wherein the first wireless transceiver supports a substantiallynon-deterministic media access protocol and the second wirelesstransceiver supports a substantially deterministic media accessprotocol.
 20. The access point of claim 11, wherein the first wirelesstransceiver and the second wireless transceiver support substantiallydistinct non-deterministic media access protocols.
 21. The access pointof claim 11, wherein the first wireless transceiver and the secondwireless transceiver operate independently to form a first communicationcell and a second communication cell.
 22. The access point of claim 11,wherein the control circuit synchronizes transmissions on the firstradio channel and the second radio channel to minimize conflicts betweentransmissions on one wireless transceiver and receipts on the otherwireless transceiver.
 23. The access point of claim 11, wherein thewired link is a local area network.
 24. An access point for establishingcommunications with a wired link, the access point comprising: a firstwireless transceiver operating to establish a first wireless cell; asecond wireless transceiver operating to establish a second wirelesscell; the first and second wireless transceivers being located such thatthe first and second cells are substantially overlapping; a controlcircuit that communicatively couples the first and second wirelesstransceivers to one another; a wired transceiver that communicativelycouples the control circuit to the wired link; and the control circuitcommunicatively couples the first wireless transceiver and the wiredtransceiver. 25 The access point of claim 24, wherein the first andsecond wireless transceivers each comprise processing circuitry thatsupports a communication protocol.
 26. The access point of claim 24,wherein the control circuit allows communications between the firstwireless transceiver and the second wireless transceiver exclusive ofthe wired link.
 27. The access point of claim 24, wherein the firstwireless transceiver supports a substantially non-deterministic mediaaccess protocol and the second wireless transceiver supports asubstantially deterministic media access protocol.
 28. The access pointof claim 24, wherein the first wireless transceiver and the secondwireless transceiver support substantially distinct non-deterministicmedia access protocols.
 29. A communication network comprising: a wiredLAN; a plurality of access point coupled via the wired LAN, each of theplurality of access points comprising: a housing; a control circuitdisposed in the housing; a wired transceiver, disposed in the housing,that is communicatively coupled to the control circuit and the wiredlink; a first wireless transceiver, disposed in the housing, that iscommunicatively coupled to the control circuit and the first roamingwireless device, the first roaming wireless device operating on a firstwireless communication channel; and a second wireless transceiver,disposed in the housing, that is communicatively coupled to the controlcircuit and the second roaming wireless device, the second roamingwireless device operating on a second wireless communication channel;and the control circuit accommodates communications between the firstwireless transceiver and the second wireless transceiver exclusive ofthe wired link; a first roaming wireless device comprising a thirdwireless transceiver that operates on the first wireless communicationchannel; and a second roaming wireless device comprising a fourthwireless transceiver that operates on the second wireless communicationchannel.
 30. The communication network of claim 29, wherein the firstroaming device operates only on the first wireless communicationchannel.
 31. The communication network of claim 29, wherein the firstroaming wireless device and the second roaming wireless device havedifferent transmission characteristics.
 32. The communication network ofclaim 29, wherein the first roaming wireless device and the secondroaming wireless device incorporate different data throughputcapabilities.
 33. The communication network of claim 29, wherein thefirst roaming wireless device and the second roaming wireless deviceoperate independently to form a first communication cell and a secondcommunication cell, respectively.
 34. The communication network of claim29, wherein the radius of the first communication cell substantiallyequals the radius of the second communication cell.
 35. Thecommunication network of claim 29, wherein the wired transceiveraccommodates communication with an Ethernet network.
 36. Thecommunication network of claim 29, wherein the wired transceiveraccommodates communication with a token-ring network.
 37. Thecommunication network of claim 29, wherein the wired transceiveraccommodates communication with an asynchronous transfer mode network.38. The communication network of claim 29, wherein the wired transceiveraccommodates communication with a packetized network.
 39. Thecommunication network of claim 29, wherein the first wirelesstransceiver supports a substantially non-deterministic media accessprotocol and the second wireless transceiver supports a substantiallydeterministic media access protocol.
 40. The communication network ofclaim 29, wherein the first wireless transceiver and the second wirelesstransceiver support substantially distinct non-deterministic mediaaccess protocols.
 41. The communication network of claim 29, wherein thethird wireless transceiver is a PCMCIA card.
 42. A communication system,comprising: a wired LAN; a plurality of access point coupled via thewired LAN, each of the plurality of access points comprising: a housing;a control circuit disposed in the housing; a wired transceiver, disposedin the housing, that is configurable to communicatively couple thecontrol circuit to a wired local area network; a first wirelesstransceiver, disposed in the housing, that is communicatively coupled tothe control circuit, the first wireless transceiver operating pursuantto a substantially deterministic, time bounded wireless communicationprotocol; and a second wireless transceiver, disposed in the housing,that is communicatively coupled to the control circuit, the secondwireless transceiver operating pursuant to a substantiallynon-deterministic contention access wireless communication protocol; anda plurality of roaming wireless devices that each wirelessly communicatewith at least one of the first and second wireless transceivers.